Interpretive Handbook

Test
9624 :
Trazodone, Serum

Trazodone is indicated for treatment of depression characterized by a prominent and persistent dysphoric mood that interferes with daily function.

Trazodone is administered in oral doses of 150 to 400 mg/day in divided doses to yield blood levels of 650 to1,500 ng/mL that correlate with response to the drug.

Within the therapeutic range, trazodone is 93% protein bound. It exhibits a volume of distribution of 1.0 L/kg and an elimination half-life of 6 hours. Oral bioavailability ranges from 60% to 90%.

Priapism and hypotension are side effects that occur at therapeutic doses of the drug.

There are no known major drug interactions that affect the pharmacology of trazodone.

Toxicity is characterized by respiratory arrest, seizure, and electrocardiogram changes typical of atrioventricular conduction block. There is no specific antidote to trazodone overdose; treatment is symptomatic and supportive.

Most individuals display optimal response to trazodone when serum levels are 650 to 1,500 ng/mL. Some individuals may respond well outside of this range, or may display toxicity within the therapeutic range, thus interpretation should include clinical evaluation. Toxic levels have not been well established. Therapeutic ranges are based on samples drawn at trough (ie, immediately before the next dose.)